1. Field of Invention
The present invention relates to an ink jet recording apparatus provided with plural ink jet heads, such as a multicolor printer, and more particularly to an ink jet recording apparatus provided with a compact sucking mechanism, which may be called a purging mechanism, for recovering an ejection state.
2. Description of Related Art
Recording apparatuses using an ink jet head generally need a mechanism for preventing deterioration in the ejecting state due to ink drying of the ink jet head, generation of air bubbles and the like, and for recovering the ink ejection state. Recording apparatuses are accordingly provided with a cap to cover a nozzle face of the ink jet head, which communicates with a suction pump. When recording is not performed, for example, to wait for transmission of recording data, the nozzle faces are covered and protected by the cap. In case of the ink ejection state deteriorating, a suction removal operation of ink is conducted by the suction pump to recover the defective ink ejection state.
Recently, ink jet recording apparatuses having plural ink jet heads have widely been used for color printing. Such an apparatus requires caps in a number corresponding to the number of ink jet heads in view of protecting the nozzle faces in a stand-by state. However, a recovery operation of the ink ejection by the suction pump is not always needed for all ink jet heads at the same time. If all caps are made to communicate with a common suction pump, therefore, the ink suction (purge) is executed even on the ink jet head in which the ink is not defective, resulting in a large waste of ink.
For example, Japanese patent application laid-open No. 5-27006 discloses an ink jet printer which is provided with caps for only a protecting operation, not communicating with the suction pump, in the same number as that of ink jet heads and, separately from those caps, a cap for only a purging operation, communicating with the suction pump. Specifically, the ink jet heads are covered respectively by the protecting caps in a stand-by state and only the ink jet head to be purged is covered by the purging cap. This makes it possible to avoid needless ink suction on the head for which the ink is not deteriorated.
In an ink jet recording apparatus disclosed in Japanese patent application laid-open No. 7-32599, there are provided caps in the same number as that of ink jet heads, in which a part of the caps is made to communicate with a suction pump so as to have a purging function.
However, the conventional ink jet recording apparatuses mentioned above have the following disadvantages.
The ink jet printer mentioned in the Japanese patent application laid-open No. 5-270006 is provided with caps in the number more than that of ink jet heads, needing a large space around the ink jet heads, thus resulting in an increase in size of the entire apparatus.
The ink jet recording apparatus in the Japanese patent application laid-open No. 7-32599, having no problem in size of the apparatus, unavoidably needs a driving motor only for advancing and retracting caps, separately from one for transporting a recording medium such as paper, causing a problem in cost and weight of the apparatus.